Ok, so I have a 2000 Lightning and as I am sure all of you are aware, the stock third brake lamp is quite ugly. I recently purchased the LED model that came in I believe 2003-04. I had it running for a while, and after about a week, I noticed one of the bulbs was burnt out. I thought it was just defective until I looked inside the fixture.

What had happened was that the bulbs were melting the reflectors and in turn the bulbs were cracking and causing the whole lamp to melt. I found this very odd and just had the company send me a replacement. I got the replacement and once again stuck it in.

I have now been running it for about 5 days and once again, a bulb burnt out, and once again, I thought it was a defective bulb. Sure enough, I have another melted lamp.

Is there a reason this is happening? Does my L give off too much power to the stock lamp and in turn causing this one to overheat and melt? Please help because I do not know if I can get another replacement and these things are not cheap. Thanks.

 

I bought the OEM Lightning LED 3rd brake light off ebay for $90 4 years ago and have not had a problem.

 

Ok, is there any way to test if I have an issue? I mean its not like they are on very often, and the LEDs still work fine...

 

Hi Chuck

I'm curious if this is an OEM or aftermarket part?

I think I would start by removing one of the lamps and checking the wattage (I'd think it would be labeled on the bulb). If the bulb wattage is too high, meaning higher than stock-- that could definitely cause the reflector to melt. If it's an aftermarket fixture, I might be suspicious of the quality of the reflector.

I'm sure some others have ideas...

 

It is a Genuine Ford Part. The bulbs are the stock ones that come with the part which is why it is confusing me. The bulbs are 921s which I think are supposed to be 18w.

 

Very interesting.

Here's some data, hopefully it may help.

I don't have the manual with me at work for my 2002, but the online parts stores seem to think that my "high mount stop light" (which I assume is the lamp that is on with the interior, since I also have LED brake light) is a 912, not a 921.

From what I can tell,

912 is 1A * 12.8V which would mean 12.8W
921 is 1.4A * 12.8V which would mean 17.92w

IF that is the case, there's a significant wattage difference. Perhaps someone else can chime in today with which bulbs are in their truck... otherwise I will try to check when I get home. Is it difficult to get the lamps out of the assembly?

 

No, and that might be my problem. My bulbs in the stock lamp are 921s it says it right on the bulb. However, both lamps I've bought, have 921s as well...

 

Do you have the manual? I know you have a different assembly than the stocker, but I was just curious if it lists the part. I will check once home.

Autozone & PartsAmerica seem to indicate a 912 on their website (seems to be same for dome light and the High mount stop light), and I can't find any other lamp type in the list that seems to match what you are looking for.

The base of the bulbs seems to look the same, given the illustration.. but it's very wierd that the lamp came with 921's if that's not what's supposed to be there.

 

I am unclear as to what you want me to look up.

Also, my dome is NOT a 912 or any bulb like that it is the 578 bulb which is one of these

 

I didn't say the dome WAS a 912, I said that they "seem to indicate" the bulb as a possible dome light. I was supposing that perhaps they classify it as a dome light since the cargo lamps come on with the interior lights.

But here's your answer: I called my local dealer, they said the cargo lamps are 912. They also said that a higher wattage bulb can melt the housing, and potentially cause wiring concerns.

 

Ok so then I assume I should tell the seller that for some reason they are giving me the wrong bulbs? And then go out and buy some 912s? Thanks for all your help.

 

Thats what I think I would do... If you've been forced to buy more than one of these assemblies due to this problem, you may want to try and negotiate for the extra $$ that you have had to spend. As you mentioned, they are not cheap.

Like I mentioned, the Ford parts guy @ my dealer said it's supposed to be 912's in there, but you could most certainly call the parts dept @ your local dealer to double-verify.

I honestly don't know why the people you got your parts from would put the higher wattage bulbs in... It seems dangerous.

 

I got the replacement for free. I am going to notify the seller that something is wrong and that they should give me a new one. I will not pay an extra 70 bucks if it was their fault. I will double check that the bulbs are 921 and not 912. Thanks for all your help.

 

My stock 2002 housing has yellow, cracked lenses. The bulb heat makes too much for the housing.

But if yours is melting that fast, I have to wonder if they are staying on or something.

I bought a replacement, but will not be installing it until I replace the stock bulbs with LEDs.

 

Very good point, Tim. Do you know whether you have the 912 or the 921 in yours?

I didn't even check mine last night (since I spoke to the parts counter)-- but I will tonight. Hopefully the bulbs aren't too hard to get at in that assembly. I assume I have to take it apart.